[MARMAM] Publication on winter foraging ecology of southern elephant seals

Sara Labrousse sara.labrousse at gmail.com
Fri Feb 12 16:08:50 PST 2016


Dear all,

My co-authors and I are pleased to bring to your attention the following
publication :

Labrousse, S., Vacquié-Garcia, J., Heerah, K., Guinet, C., Sallée, J.-B.,
Authier, M., Picard, B., Roquet, F., Bailleul, F., Hindell, M., Charrassin,
J.-B., 2015. *Winter use of sea ice and ocean water mass habitat by
southern elephant seals: The length and breadth of the mystery.* *Progress
in Oceanography* 137, 52–68. doi:10.1016/j.pocean.2015.05.023
<http://dx.doi.org/10.1016/j.pocean.2015.05.023>

Abstract
Understanding the responses of animals to the environment is crucial for
identifying critical foraging habitat. Elephant seals (*Mirounga leonina*)
from the Kerguelen Islands (49 °20'S, 70 °20'E) have several different
foraging strategies. Why some individuals undertake long trips to the
Antarctic continent while others utilize the relatively close frontal zones
is poorly understood. Here, we investigate how physical properties within
the sea ice zone are linked to foraging activities of southern elephant
seals (SES). To do this, we first developed a new approach using indices of
foraging derived from high temporal resolution dive and accelerometry data
to predict foraging behaviour in an extensive, low resolution dataset from
CTD-Satellite Relay Data Loggers (CTD-SRDLs). A sample of 37 post-breeding
SES females were used to construct a predictive model applied to demersal
and pelagic dive strategies relating prey encounter events (PEE) to dive
parameters (dive duration, bottom duration, hunting-time, maximum depth,
ascent speed, descent speed, sinuosity, and horizontal speed) for each
strategy. We applied these models to a second sample of 35 seals, 20 males
and 15 females, during the post-moult foraging trip to the Antarctic
continental shelf between 2004 and 2013, which did not have fine-scale
behavioural data. The females were widely distributed with important
foraging activity south of the Southern Boundary Front, while males
predominately travelled to the south-eastern part of the East Antarctica
region. Combining our predictions of PEE with environmental features (sea
ice concentration, water masses at the bottom phase of dives, bathymetry
and slope index) we found higher foraging activity for females over
shallower seabed depths and at the boundary between the overlying Antarctic
Surface Water (AASW) and the underlying Modified Circumpolar Deep Water
(MCDW). Increased biological activity associated with the upper boundary of
MCDW, may provide overwintering areas for SES prey. Male foraging activity
was strongly associated with pelagic dives within the Antarctic Slope Front
where upwelling of nutrient rich Circumpolar Deep Water onto surface water
may enhance and concentrate resources. A positive association between sea
ice and foraging activity was found for both sexes where increased
biological activity may sustain an under-ice ecosystem. Variability of the
East Antarctic sea ice season duration is likely a crucial element to allow
air-breathing predators to benefit from profitable prey patches within the
pack ice habitat.

A PDF may be obtained from Science Direct:
http://www.sciencedirect.com/science/article/pii/S0079661115001287

or requests for reprints can be sent to: sara.labrousse at utas.edu.au

Kind regards,
Sara Labrousse

-- 
Sara Labrousse
PhD candidate
UPMC - LOCEAN
4 place Jussieu
Boite 100 - 45-55 4ème étage
75252 Paris cedex 05
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